ARM: add mach-asm9260

ARM: add mach-asm9260

it is low cost (?) SoC targeted for market in China and India which
trying to compete with AT91SAM9G25.

Here is some info:
http://www.alphascale.com/index.asp?ics/615.html

One of products:
http://www.aliexpress.com/store/product/2014-hot-sales-FREE-SHIPPING-new-Purple-core-ARM9-development-board-ASM9260T-SDRAM-power-line/433637_1931495721.html

In some cases this SoC looks similar to iMX23/iMX28. But currently it makes no
sense to merge mach code of this devices. Especially because most differences
are already collected mach-mxs folder.

Signed-off-by: Oleksij Rempel <linux@rempel-privat.de>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>